Testing Strategies: Building Confidence in Your Code

Tests are your safety net. They let you ship with confidence and refactor fearlessly.

The Testing Pyramid

Unit Tests (Foundation)

• Fast and isolated
• Test individual functions/components
• High coverage, low cost

Integration Tests (Middle)

• Test component interactions
• Database queries
• API endpoints

E2E Tests (Top)

• Test complete user flows
• Slower but comprehensive
• Focus on critical paths

What to Test

Test Behavior, Not Implementation

❌ Bad: Testing internal state

expect(component.state.isOpen).toBe(true)

✅ Good: Testing user-visible behavior

expect(screen.getByRole('dialog')).toBeVisible()

Testing React Components

React Testing Library

Focus on user interactions:

test('submits form with user data', async () => {
  render(<SignupForm />)
  
  await userEvent.type(
    screen.getByLabelText(/email/i), 
    'test@example.com'
  )
  await userEvent.click(screen.getByRole('button'))
  
  expect(screen.getByText(/success/i)).toBeInTheDocument()
})

API Testing

Test your endpoints thoroughly:

• Happy paths
• Error cases
• Edge cases
• Authentication/authorization

Mocking Best Practices

• Mock external services, not your own code
• Use realistic mock data
• Keep mocks up to date

Continuous Integration

Run tests automatically:

• On every pull request
• Before deployment
• Nightly for slow tests

Test Coverage

Aim for meaningful coverage:

• 80% is a good target
• 100% isn't always practical
• Focus on critical paths

When to Skip Tests

Sometimes it's okay to skip:

• Prototypes and spikes
• Pure UI styling
• Third-party library wrappers

Conclusion

Good tests make development faster, not slower. Invest in your test suite—it's an investment in your sanity.